ehhhhh.....I hate to bust your bubble, but two things. First, that's a stock replacement 360 piston with the exception that it's forged. Secondly, it is impossible to offset grind a 3.58" crank to a 4" crank, which is what you need for a 408. So more likely than not, it's a stock stroke 360. All is not lost, because even though they are stock compression, they are nice pistons. Be good for a turbo or blower or nitrous, or you could mill the heads and deck the block some to get a little more compression. As is, they will do good to blueprint at a flat 8:1.